preparation

For crepes:

Combine all ingredients in blender. Blend until smooth. DO AHEAD: Crepe batter can be made 4 hours ahead. Cover and refrigerate. Reblend before using.

Line plate with paper towel or parchment paper. Heat 9-inch-diameter nonstick skillet with 7-inch-diameter bottom over medium heat. Add 2 tablespoons crepe batter to skillet; tilt and swirl skillet to spread batter evenly over bottom. Cook until center of crepe is cooked through and edges are lightly browned, about 1 minute. Run spatula around crepe and invert onto prepared paper-towel-lined plate. Repeat with remaining batter, placing paper towels or parchment paper between crepes. DO AHEAD: Can be made 1 day ahead. Cover and refrigerate.

For rum butter sauce:

Using electric mixer, beat sugar, butter, and salt in medium bowl until fluffy, about 2 minutes. Gradually add rum and beat until well blended. DO AHEAD: Can be made 1 day ahead. Cover and refrigerate.

For tropical fruit:

Melt butter in large nonstick skillet over medium-high heat. Add pineapple to skillet and scrape in seeds from vanilla bean; add bean. Add sugar and salt; stir until sugar dissolves and pineapple and pan juices are lightly browned, about 4 minutes. Stir in lime juice. Remove from heat. DO AHEAD: Can be made 2 hours ahead. Let stand at room temperature.